In what jar is org.postgresql.Connection ?

Hi,
The trouble is that I can´t find the org.postgresql.Connection class in posgresql.jar nor in PostgreSQL\jdbc3.jar
Could you please give me a hint where I could find it or related resources?
I am trying to run an example with the following excerpt:
Class.forName("org.postgresql.Driver");
String url = "jdbc:postgresql://" + dbhost + ":" + dbport + "/" + dbname;
conn = DriverManager.getConnection(url, dbuser, dbpass);
System.out.println("Adding geometric type entries...");
((org.postgresql.Connection)conn).addDataType("geometry","org.postgis.PGgeometry");
((org.postgresql.Connection)conn).addDataType("box3d","org.postgis.PGbox3d");
found in postgis-0.7.5
Thanks in advance
Carlos